Switched capacitor converter circuit and switching converter unit thereof

Abstract

A switched capacitor converter circuit includes: plural capacitors and plural switches which switch the connections of the plural capacitors periodically. In a first period, the plural switches control a first capacitor to be electrically connected between a first power and a second power, and control a second capacitor and a third capacitor to be electrically connected in series between the second power and a ground level. In a second period, the plural switches control the first capacitor and the second capacitor to be electrically connected in series between the second power and the ground, and control the third capacitor and the second capacitor to be electrically connected in parallel with the second power, thereby a second current of the second power is 4 times of a first current of the first power.

What is claimed is: 
     
       1. A switched capacitor converter circuit, which is configured to operably convert a first power to a second power or convert the second power to the first power; the switched capacitor converter circuit comprising:
 at least one switching converter unit; and 
 a control circuit, which is configured to operably control the at least one switching converter unit; 
 wherein the at least one switching converter unit includes:
 a plurality of capacitors including a first capacitor, a second capacitor and a third capacitor; and 
 a plurality of switches, which are configured to operably and periodically switch the connections of the plurality of capacitors according to a switching period; 
 wherein in a 4-fold conversion mode, during a first period within the switching period, the plurality of switches control the first capacitor to be electrically connected between the first power and the second power and control the second capacitor and the third capacitor to be electrically connected in series between the second power and a ground level; 
 wherein in the 4-fold conversion mode, during a second period within the switching period, the plurality of switches control the first capacitor and the second capacitor to be electrically connected in series between the second power and the ground level and control the third capacitor to be electrically connected in parallel with the second power; 
 whereby power conversion between the first power and the second power is executed through periodically repeating the switching period, so that in the 4-fold conversion mode, a first voltage of the first power is 4 times of a second voltage of the second power, whereas, a second current of the second power is 4 times of a first current of the first power. 
 
 
     
     
       2. The switched capacitor converter circuit of  claim 1 , wherein the plurality of switches include: first to eighth switches, wherein the first switch, the second switch, the third switch and the fourth switch are sequentially coupled in in series between the first power and the second power, and wherein the first switch and the second switch are coupled to a first node in between, whereas, the second switch and the third switch are coupled to a second node in between, whereas, the third switch and the fourth switch are coupled to a third node in between, and wherein the fifth switch and the sixth switch are coupled in series between the second power and the ground level and are coupled to a fourth node in between, wherein the seventh switch and the eighth switch are coupled in series between the second power and the ground level and are coupled to a fifth node in between; wherein the first capacitor is coupled between the first node and the fourth node, whereas, the second capacitor is coupled between the second node and the fifth node, whereas, the third capacitor is coupled between the third node and the fourth node;
 wherein in the 4-fold conversion mode, during the first period, the first switch, the third switch, the fifth switch and the eighth switch are ON, whereas, the second switch, the fourth switch, the sixth switch and the seventh switch are OFF, thus controlling the first capacitor to be electrically connected between the first power and the second power and thus controlling the second capacitor and the third capacitor to be electrically connected in series between the second power and the ground level; 
 wherein in the 4-fold conversion mode, during the second period, each of the first switch to the eighth switch is operated according to a state complementary to a state during the first period, so as to control the first capacitor and the second capacitor to be electrically connected in series between the second power and the ground level and control the third capacitor to be electrically connected in parallel with the second power; 
 whereby the power conversion between the first power and the second power is executed through periodically repeating the switching period. 
 
     
     
       3. The switched capacitor converter circuit of  claim 2 , wherein in a 3-fold conversion mode, during a first period within the switching period, the first switch, the second switch, the fourth switch, the sixth switch and the seventh switch are ON, whereas, the third switch, the fifth switch and the eighth switch are OFF, thus controlling the first capacitor to be electrically connected between the first power and the ground level and thus controlling the second capacitor and the third capacitor to be electrically connected in series between the first power and the second power;
 wherein in the 3-fold conversion mode, during the second period, each of the first switch to the eighth switch is operated according to a state complementary to a state during the first period, so as to control a first end of the first capacitor to be floating, and so as to control a second end of the first capacitor to be electrically connected with the second power, and so as to control the second capacitor and the third capacitor to be electrically connected in series between the second power and the ground level; 
 whereby the power conversion between the first power and the second power is executed through periodically repeating the switching period, so that in the 3-fold conversion mode, a first voltage of the first power is 3 times of a second voltage of the second power, whereas, a second current of the second power is 3 times of a first current of the first power. 
 
     
     
       4. The switched capacitor converter circuit of  claim 3 , wherein the first switch includes: a first transistor and a second transistor connected in series to each other, wherein a direction of a body diode of the first transistor is opposite to a direction of a body diode of the second transistor. 
     
     
       5. The switched capacitor converter circuit of  claim 2 , wherein a first part of the plurality of switches have a first withstand voltage, and wherein a peak voltage that the first part of the plurality of switches are required to withstand during power conversion is defined as a first peak voltage, wherein a second part of the plurality of switches have a second withstand voltage, and wherein a peak voltage that the second part of the plurality of switches are required to withstand during power conversion is defined as a second peak voltage, wherein the first peak voltage is 2 times of the second peak voltage. 
     
     
       6. The switched capacitor converter circuit of  claim 5 , wherein a number of the first part of the plurality of switches is smaller than ½ of a total number of the plurality of switches, whereas, a number of the second part of the plurality of switches is greater than ½ of the total number of the plurality of switches. 
     
     
       7. The switched capacitor converter circuit of  claim 5 , wherein in the 4-fold conversion mode, the first part of the plurality of switches include: the second switch and the third switch, whereas, the second part of the plurality of switches include: the first switch and the fourth switch to the eighth switch. 
     
     
       8. The switched capacitor converter circuit of  claim 5 , wherein a relationship among the first peak voltage, the second peak voltage, the first withstand voltage and the second withstand voltage is represented as follow:
 the first withstand voltage is greater than the first peak voltage; and 
 the first peak voltage is greater than the second withstand voltage; and 
 the second withstand voltage is greater than the second peak voltage. 
 
     
     
       9. The switched capacitor converter circuit of  claim 2 , wherein in a 2-fold conversion mode, the second switch and the third switch are always ON;
 wherein in the 2-fold conversion mode, during a first period within the switching period, the first switch, the fifth switch and the seventh switch are ON, whereas, the fourth switch, the sixth switch and the eighth switch are OFF, thus controlling the first capacitor, the second capacitor and the third capacitor to be electrically connected in parallel between the first power and the second power; 
 wherein in the 2-fold conversion mode, during a second period within the switching period, the first switch and each of the fourth switch to the eighth switch are operated according to a state complementary to a state during the first period, so as to control the first capacitor, the second capacitor and the third capacitor to be electrically connected in parallel between the second power and the ground level; 
 whereby the power conversion between the first power and the second power is executed through periodically repeating the switching period, so that in the 2-fold conversion mode, a first voltage of the first power is 2 times of a second voltage of the second power, whereas, a second current of the second power is 2 times of a first current of the first power. 
 
     
     
       10. The switched capacitor converter circuit of  claim 2 , wherein in a bypass mode, the first switch to the fourth switch are ON, whereas, the fifth switch to the eighth switch are OFF, so that the first power is directly electrically connected to the second power. 
     
     
       11. The switched capacitor converter circuit of  claim 2 , wherein the at least one switching converter unit includes: a first switching converter unit and a second switching converter unit, which are coupled in parallel between the first power and the second power, wherein each of the first switching converter unit and the second switching converter unit switches respective corresponding plurality of switches by interleaving phases, so as to execute power conversion between the first power and the second power. 
     
     
       12. The switched capacitor converter circuit of  claim 1 , wherein in the 4-fold conversion mode, during a steady state, a ratio among a voltage across the first capacitor, a voltage across the second capacitor, and a voltage across the third capacitor is 3:2:1. 
     
     
       13. A switching converter unit, which is configured to operably convert a first power to a second power or convert the second power to the first power; the switching converter unit comprising:
 a plurality of capacitors including a first capacitor, a second capacitor and a third capacitor; and 
 a plurality of switches, which are configured to operably and periodically switch the connections of the plurality of capacitors according to a switching period; 
 wherein in a 4-fold conversion mode, during a first period within the switching period, the plurality of switches control the first capacitor to be electrically connected between the first power and the second power and control the second capacitor and the third capacitor to be electrically connected in series between the second power and a ground level; 
 wherein in the 4-fold conversion mode, during a second period within the switching period, the plurality of switches control the first capacitor and the second capacitor to be electrically connected in series between the second power and the ground level and control the third capacitor to be electrically connected in parallel with the second power; 
 whereby power conversion between the first power and the second power is executed through periodically repeating the switching period, so that in the 4-fold conversion mode, a first voltage of the first power is 4 times of a second voltage of the second power, whereas, a second current of the second power is 4 times of a first current of the first power. 
 
     
     
       14. The switching converter unit of  claim 13 , wherein the plurality of switches include: first to eighth switches, wherein the first switch, the second switch, the third switch and the fourth switch are sequentially coupled in in series between the first power and the second power, and wherein the first switch and the second switch are coupled to a first node in between, whereas, the second switch and the third switch are coupled to a second node in between, whereas, the third switch and the fourth switch are coupled to a third node in between, and wherein the fifth switch and the sixth switch are coupled in series between the second power and the ground level and are coupled to a fourth node in between, wherein the seventh switch and the eighth switch are coupled in series between the second power and the ground level and are coupled to a fifth node in between; wherein the first capacitor is coupled between the first node and the fourth node, whereas, the second capacitor is coupled between the second node and the fifth node, whereas, the third capacitor is coupled between the third node and the fourth node;
 wherein in the 4-fold conversion mode, during the first period, the first switch, the third switch, the fifth switch and the eighth switch are ON, whereas, the second switch, the fourth switch, the sixth switch and the seventh switch are OFF, thus controlling the first capacitor to be electrically connected between the first power and the second power and thus controlling the second capacitor and the third capacitor to be electrically connected in series between the second power and the ground level; 
 wherein in the 4-fold conversion mode, during the second period, each of the first switch to the eighth switch is operated according to a state complementary to a state during the first period, so as to control the first capacitor and the second capacitor to be electrically connected in series between the second power and the ground level and control the third capacitor to be electrically connected in parallel with the second power; 
 
       whereby the power conversion between the first power and the second power is executed through periodically repeating the switching period. 
     
     
       15. The switching converter unit of  claim 14 , wherein in a 3-fold conversion mode, during a first period within the switching period, the first switch, the second switch, the fourth switch, the sixth switch and the seventh switch are ON, whereas, the third switch, the fifth switch and the eighth switch are OFF, thus controlling the first capacitor to be electrically connected between the first power and the ground level and thus controlling the second capacitor and the third capacitor to be electrically connected in series between the first power and the second power;
 wherein in the 3-fold conversion mode, during the second period, each of the first switch to the eighth switch is operated according to a state complementary to a state during the first period, so as to control a first end of the first capacitor to be floating, and so as to control a second end of the first capacitor to be electrically connected with the second power, and so as to control the second capacitor and the third capacitor to be electrically connected in series between the second power and the ground level; 
 whereby the power conversion between the first power and the second power is executed through periodically repeating the switching period, so that in the 3-fold conversion mode, a first voltage of the first power is 3 times of a second voltage of the second power, whereas, a second current of the second power is 3 times of a first current of the first power. 
 
     
     
       16. The switching converter unit of  claim 15 , wherein the first switch includes: a first transistor and a second transistor connected in series to each other, wherein a direction of a body diode of the first transistor is opposite to a direction of a body diode of the second transistor. 
     
     
       17. The switching converter unit of  claim 14 , wherein in a 2-fold conversion mode, the second switch and the third switch are always ON;
 wherein in the 2-fold conversion mode, during a first period within the switching period, the first switch, the fifth switch and the seventh switch are ON, whereas, the fourth switch, the sixth switch and the eighth switch are OFF, thus controlling the first capacitor, the second capacitor and the third capacitor to be electrically connected in parallel between the first power and the second power; 
 wherein in the 2-fold conversion mode, during a second period within the switching period, the first switch and each of the fourth switch to the eighth switch are operated according to a state complementary to a state during the first period, so as to control the first capacitor, the second capacitor and the third capacitor to be electrically connected in parallel between the second power and the ground level; 
 whereby the power conversion between the first power and the second power is executed through periodically repeating the switching period, so that in the 2-fold conversion mode, a first voltage of the first power is 2 times of a second voltage of the second power, whereas, a second current of the second power is 2 times of a first current of the first power.